This invention relates generally to air chucks, and more particularly, is directed to an improved air chuck that permits quick and easy replacement of the air bladder therein.
Air chucks have conventionally been used to hold rolls of web material on machines, while permitting unwinding and rewinding of the webs from the rolls.
Specifically, a conventional air chuck includes a central core having an air bladder wrapped therearound. The air bladder is secured by metal bands which press down at opposite ends of the air bladder to secure the air bladder to the core. An air passage is provided in the central core for supplying air against the inner surface of the air bladder, thereby deforming the same radially outwardly. A plurality of leaves are mounted in a lengthwise direction of the air chuck on top of the bladder, and are adapted to move radially outward by a small amount. When air is supplied through the air passage, the air bladder is inflated outwardly and presses the leaves outwardly so as to securely hold the roll of web material on the air chuck.
However, a problem with such arrangement is that the air bladder often gets worn out and must be replaced. This is a long and complicated procedure. Specifically, as a first step, the leaves must all be removed. Then, the metal bands which hold the ends of the air bladder must be removed, followed by removal of the air bladder. A reverse procedure is then performed, by applying a new air bladder, securing the same by the metal bands, and then securing the leaves thereon.
This procedure can take upwards of two or more hours, and results in substantial downtime of the web winding machine.